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Burnham and Weil make small wall hung cast iron boilers. No condensing, no modulating. Baxi and Takagi make units that modulate but don't condense. It's your call cheaper system up front or more savings with condensing / modulating. Gas is not going to get cheaper and has almost doubled for some.

John

We just showed our new wall hung, condensing, modulating gas boiler, for the first time, at this weeks ASHRAE show in Chicago. It has our own, 1" aluminum tube, serpantine fin coil (slab style) heat exchanger with the Ultra/Munchkin style gas train on it, firing DOWN through the heat exchanger, PVC flue, spark ignition, built in reset controller, and competitively priced (but not yet announced). It will only be sold through heating wholesalers.

I'll get you more info on the Bobcat, by Slant/Fin, when I can get it.

Can't wait to see it Noel. Nice to see Slant/fin comming into this market.

Fitz: As you can see. Every manufacturer is moving to modulating/condensing gas boilers. Been the standard for years in Europe. States are starting to enact higher min efficency standards. I would never put in an 80% gas boiler when a therm is already $2 for some people. You know the gas companies will never drop the prices.

Originally posted by fritzl I suppose I should consider myself lucky @ $1.12/therm, so far ....

What makes a modulating/condesing better than a "traditional" boiler?
I don't care about the expense now if it's more efficient and can be serviced in our shack.

In lay terms.

It takes a lot of BTU to raise the temp of water. You want to match the heat loss, not produce more heat that just vents out the boiler. This is what happens when you raise a boiler to 180° then the circulator shuts off: the hot boiler and piping lose heat to the greater outdoors.

Now if you only need 120° water today, the boiler can modulate down. Problem is so much heat is being pulled out of the nat gas/LP that your flue gas is mostly water vapor. When it hits the cold exhaust pipe, you get condensation. SO you need a stainless steel or aluminum heat exchanger that can handle this.

So electronic controls, variable speed inducer fan, variable gas valve, all add up to extra cost. You had to decide if that 15% saving of your gas bill over 15-20 years is worth it. Many say the saving is even greater since the AFUE test is a very specific test at 140° boiler temps. At lower boiler temps you could save even more.

The house itself was blown with cellulose 3 years ago, on the entire 1st floor. The 2nd floor is only a bedroom. It has original glass batts that seem to have been done right, based on exposure. The 2nd floor roof may get redone when we add a roof vent.

But the big problem is under the house, which is 20% basement, 20% zero access crawl and 60% limited access crawl. Can the SPF be applied in these situations? Does it need to be "sealed" itself or clean sawn for any reason?
I believe there is a kind of barrier on the ground of the crawl space, but I wouldn't swear to it.

It would seem to me in this day and age that the word "no" or "not possible" is a term used only be either the close minded or the plain lazy.

I myself dread the days when a small crawlspace install is coming up, but I none the less go and do it.

It sounds to me like you want radiant 'cuz you know it's the best and that's what you want. You also sound willing to take measures to get what you want. This adds up to a smart consumer, and a flexable mindset.

Which is why I would suggest other options and you can take what you will from them.

It sounds to me like your first option in this remodel is to look into expanding the crawlspace. I know it might sound like alot to the average laymen, but it's usually not all that bad once the numbers are in. And considering the outcome of having full access under the house..........it seems like a viable option at the very least.

As a heating and cooling contractor who deals mainly with the extream high end homes and projects, I will say that many times there is an answer.....it's only a matter of you asking the right person who has it !

At least 90% of the homes I do have radiant heating in them. I have learned quite a bit about it since working with these contracts. Which is why I say that if you can achieve even the smallest amount of room under your home (crawlspace), then radiant is an easy option. The underfloor plates can easily be installed on one's back and icynene will obviously be easy as well.

And with this new underfloor room you'll have aquired, air conditioning will also be a simple option as well. Unico can easily be installed in a space like this and provide you with excellent comfort, not to mention can be used as a suplimental backup heat if your home is one with large foyers and greatrooms and areas of such nature if your contractor has any doubts as to radiant abilities in the coldest days.

In short, achieving a little more room under the house can get you alot more comfort in your home.